#ifndef _UTIL_H
#define _UTIL_H 1
+// Various utilities.
+
#include <stdio.h>
#include <stdlib.h>
#include <string>
-#include <GL/gl.h>
+#include "opengl.h"
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
-// assumes h in [0, 2pi> or [-pi, pi>
+// Converts a HSV color to RGB. Assumes h in [0, 2pi> or [-pi, pi>
void hsv2rgb(float h, float s, float v, float *r, float *g, float *b);
+// Converts a HSV color to RGB, but keeps luminance constant
+// (ie. color luminance is as if S=0).
+void hsv2rgb_normalized(float h, float s, float v, float *r, float *g, float *b);
+
// Column major (same as OpenGL).
typedef double Matrix3x3[9];
+// Read a file from disk and return its contents.
+// Dies if the file does not exist.
std::string read_file(const std::string &filename);
+
+// Compile the given GLSL shader (typically a vertex or fragment shader)
+// and return the object number.
GLuint compile_shader(const std::string &shader_src, GLenum type);
+
+// Compute a * b.
void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
+
+// Compute M * [x0 x1 x2]'.
+void multiply_3x3_matrix_float3(const Matrix3x3 M, float x0, float x1, float x2, float *y0, float *y1, float *y2);
+
+// Compute m^-1. Result is undefined if the matrix is singular or near-singular.
void invert_3x3_matrix(const Matrix3x3 m, Matrix3x3 result);
+
+// Print a 3x3 matrix to standard output. Useful for debugging.
void print_3x3_matrix(const Matrix3x3 m);
#ifdef NDEBUG